For increasing the recording density of magnetic recording, it is required to locally heat a magnetic recording medium and decrease the coercivity of the magnetic recording medium for facilitating recording. For local heating, it is desirable to use a near-field light.
Japanese Unexamined Patent Application Publication No. 2001-255254 and Japanese Patent Nos. 4032689 and 4104584 disclose a technology of generating a near-field light using surface plasmon with a metallic scatterer (plasmon generator in the present invention) irradiated with a light.
In generating a near-field light, the feature that the surface plasmon tends to propagate along a sharp edge in a concentrated manner should be utilized, so that in order to provide the metallic scatterer with a sharp edge, it is effective to modify its shape into a triangular prism.
On the other hand, however, since the edge tends to overheat excessively, thermal deformation of the metallic scatterer becomes a major problem.